Evolving Languages Faster with Type Tailoring

Programming languages are evolving slowly due to the limitations of their type systems in understanding domain-specific aspects like regular expressions. This leads to errors and inefficiencies when working with specialized code. One proposed solution is "Type Tailoring," a method to teach the type system new tricks using metaprogramming tools without requiring changes to the language's core. By tailoring types to specific tasks, programmers can improve code efficiency and correctness. The process involves programming the elaboration step after macroexpansion, leveraging procedural macros, and working with AST datatypes. Essential features for successful type tailoring include type checking after elaboration, elaboration-time computation, and an AST datatype. Additional features like hygienic macros, metadata handling, and controlling expansion order enhance the tailoring process. While no language currently supports all these features, the concept of type tailoring opens up possibilities for improving language flexibility and efficiency without extensive changes to the core language design.